A hepatitis E outbreak caused by a temporary interruption in a municipal water treatment system, Baripada, Orissa, India, 2004

In January 2004, we investigated a cluster of acute hepatitis in Baripada, Orissa, India. Between January and March 2004, 538 cases (definition: fever with loss of appetite and jaundice) were reported (attack rate: 263 per 100 000, 5 deaths, case fatality rate: 0.93%). Forty-seven of 48 sera were positive for IgM antibodies to hepatitis E virus. Cases peaked in February 2004 and decreased rapidly, suggesting a common source outbreak. Five neighbourhoods supplied by a common water supply were most affected. Ninety-one percent of the 538 cases and 30% of 538 unaffected controls reported drinking water from one source (odds ratio 31,95% CI 27-48). The neighbourhood's water was pumped directly from a river and had not been treated during a 10-day period in early January (1 month before the peak of the outbreak) because of a strike at the treatment plant. This large hepatitis E outbreak was associated with drinking untreated raw river water. Measures must be in place to check the quality of municipal water and to ensure essential services in case of strikes. (c) 2009 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.